<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
    ul li:nth-last-child(odd){background-color: mediumvioletred;}
    .top:hover{
        background-color: olivedrab;
    }
    .mid:hover{
        background-color: red;
    }
    .down:hover{
        background-color: yellow;
    }
    .line::after{
        content:"hello world";
        display: block;
    }
    .yanse::selection{
        background-color: yellow;
    }
    .baidu:link{
        color: tomato;
    }
    .input:focus{
        background-color: thistle;
    }
    </style>
</head>
<body>
      <ul>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
          <li>苹果</li>
      </ul>
      <div class="top">猕猴桃的颜色</div>
      <div class="mid">苹果的颜色</div>
      <div class="down">香蕉的颜色</div>
    <div class="line">------------------------------------------------------------------------</div>
    <div class="yanse">选择文本的时候会有颜色吗？</div>
    <a class="baidu" href="#">百度</a>
    <p>百度一下<input class="input" type="text"></p>
</body>
</html>